The present invention relates to a planetary system workpiece support as well as a surface treatment method for workpieces.
It relates fundamentally to workpiece support engineering for vacuum treatment and, in particular, vacuum coating installations. The goal of workpiece support engineering is always to move the workpieces past treatment sources, such as in particular coating sources and etching sources, such that as uniform as possible a treatment effect, in particular coating thickness and coating quality is ensured on all surfaces to be treated of the workpieces.
In the not prior published Swiss Patent Application No. 2278/97 and 1736/98, of Sep. 25, 1997 and Aug. 25, 1998, respectively, a planetary system workpiece support is described which is structured as follows:
A first system is provided which can be coupled with an installation-side driving and which is rotatable about an axis with respect to the installation.
This first rotational system is denoted in the following as sun system.
With respect to the sun system a second rotational system is provided on the latter, with rotational axis offset and parallel with respect to that of the sun system, in the following referred to as planet system, whose rotational motions are generated through the releasable engagement on the reference system formed by the installation or the chamber.
On the planetary system is provided a third rotational system, referred to in the following as moon system, which is rotatably supported with rotational axis parallel to the planetary system and sun system axis. The workpieces are set into [motion] characteristic [of the moon system] on the moon systems.
Workpiece supports of this type with threefold rotational motion are applied, in particular, in the case of relatively small workpieces in order to guide them past treatment sources stationary on the installation, such as coating sources, and to treat them uniformly on all sides.
At the above described workpiece support configuration the moon systems are set intermittently into rotational motion. This takes place thereby that with the sun system rotational motion and the superimposed planetary rotational motion they are guided past stops, which, developed like springs, act onto a ratchet-like toothing on the moon system. Inertially sluggish moon systems run therein past the stops without rotation incrementation, which has correspondingly negative consequences for the uniform workpiece treatment. The jolt-like incremental rotational motion of the moon systems generally means that, especially with relatively short treatment times, in particular coating times of tools and correspondingly provided low treatment effect, respectively small layer thickness, negative effects on the treatment homogeneity on the workpieces result due to statistical fluctuations with respect to the resilient stop engagements and the orientation resulting therefrom of the substrates to the treatment sources.